Reading Comprehension

PT122 · S3 · P4 · Q25 Maize

A free, expert breakdown of this official LSAT Reading Comprehension question.

Save & drill this skill — build targeted practice sets from questions like this one
Video walkthroughs — watch every question solved step by step
81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

Every culture that has adopted the cultivation of maize—also known as corn—has been radically changed by it.

Topic

How maize (corn) and some similar crops became so important and productive due to a unique photosynthesis process.

Framework

Answer / Explain

Main Point

The incredible productivity of maize and some other crops, which has had major impacts on societies, is due to a special adaptation in their photosynthesis process called C-4 photosynthesis, which prevents oxygen from interfering with sugar production. Most Valuable Sentence: The first sentence of paragraph 3: The last paragraph as a whole reveals the explanation for maize's productivity.

P1: The Transformative Impact of Maize

Maize (corn) has radically changed every society that adopted it, dramatically boosting food production and even supporting population growth. The reason for its influence is how productive it is compared to other crops, but the passage sets up a question: why is it so much more productive?

P2: The Biological Challenge of Photosynthesis

This paragraph explains some basics of plant photosynthesis and introduces a problem: in most plants, a key enzyme called rubisco can be interfered with by oxygen, which messes up how efficiently plants make food (sugar) from sunlight and carbon dioxide.

P3: The C-4 Photosynthesis Solution

Certain plants, like maize, have evolved a special way to avoid this problem. In these plants, the process is split up in a way that keeps oxygen away from rubisco. Carbon dioxide gets turned into a special molecule called C-4, which is then used in sugar production. This process—C-4 photosynthesis—explains why crops like maize, sugar cane, and rice can produce so much food.

25.

The passage contains information sufficient to justify inferring which one of the following?

In rice plants, atmospheric gases
Wrong Gas-Free Zone
In C-4 plants such as rice, atmospheric gases are prevented from entering the bundle sheath cells. That's why carbon has to transform into a nongas molecule to get in there and mix with rubisco. But we're told at the beginning of the last paragraph that C-4 plants "separate the places where they spit water atoms into hydrogen and oxygen from the places where they build sugars from carbon dioxide. Water molecules are split, as in all plants, in specialized chlorophyll-containing structures in the green leaf cells, but those aren't gas-proof areas. Only the bundle sheath cells where the rubisco is waiting is shielded from atmospheric gases.
17% picked this
In rice plants, oxygen produced
Out of Scope
Out of Scope: binds to other molecule We're never told that, in C-4 plants such as rice, oxygen binds to some other molecule before being released. We're told that in C-4 plants, oxygen is prevented from binding with rubisco.
4% picked this
Rice is an extremely productive
Out of Scope: various cultures
We're told that rice is extremely productive, in the final sentence. We have no idea if it nourishes large segments of the world's population or if it's cultivated by various widely separated cultures.
4% picked this
Correct
In rice plants, rubisco is
Why this is right
This is telling us something that's true of C-4 plants, of which rice is one example. In the middle of the final paragraph, we're told, The key to the process is that in these [C-4] plants, oxygen and all other atmospheric gases are excluded from the cells containing rubisco. These cells, called the bundle sheath cells, surround the vascular structures of the leaf.
Skill tested: Inference · how this choice captures the passage's function is the move to repeat next time.
74% picked this
Although rice is similar to
Unsupported Comparison
Unsupported Comparison: more cultivated Unsupported Comparison: similar nutrition All we know about rice is that it's C-4 and one of the world's most productive crops. We can't say it's similar in nutritive value nor can we say it's more widely cultivated than maize.
1% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill

LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free